All-metal check valve for air injection system

ABSTRACT

An all-metal check valve for an air injection system of an internal combustion engine includes a valve body defining a chamber between the valve inlet and the valve outlet in which a valve disc is operative to control fluid flow between an air pump and the exhaust manifolds. The valve disc has an outer ring attached to the valve body and a central valve element hingedly connected to the ring by a pair of arcuate flexible arms defined by a pair of concentric diametrically opposed C-shaped slots. The arms are normally flexed for biasing the valve element against a valve seat to block the reverse flow of exhaust gases therethrough. Injection air flow additionally flexes the arms to shift the valve element to an open position for permitting flow from the air pump to the exhaust manifolds.

United States Patent [191 Brewer Jan. 29, 1974 [75] Inventor: Robert W.Brewer, Dayton, Ohio [73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] 'Filed: June 29, 1972 [21] Appl. No.: 267,395

1,695,069 12/1928 Tuttle 137/525 X FOREIGN PATENTS OR APPLICATIONS671,526 9/1929 France 137/525.5

Primary Examiner-Al Lawrence Smith A tt omey, A gent, of 17171 Peter D.sihijfi [57 ABSTRACT An all-metal check valve for an air injectionsystem of an internal combustion engine includes a valve body defining achamber between the valve inlet and the valve outlet in which a valvedisc is operative to control fluid flow between an air pump and theexhaust manifolds. The valve disc has an outer ring attached to thevalve body and a central valve element hingedly connected to the ring bya pair of arcuate flexible arms defined by a pair of concentricdiametrically opposed C-shaped slots. The arms are normally flexed forbiasing the valve element against a valve seat to block the reverse flowof exhaust gases therethrough. Injection air flow additionally flexesthe arms to shift the valve element to an open position for permittingflow from the air pump to the exhaust manifolds.

1 Claim, 4 Drawing Figures ALL-METAL CHECK VALVE FOR AIR INJECTIONSYSTEM This invention relates to check valves and, in particular, to acheck valve for an air injection system of an internal combustion engineto prevent the reverse flow of' exhaust gases in the system.

Air injection systems wherein an engine driven air pump suppliessupplemental air to the engine exhaust ports to promote burning ofresidual combustibles require valves to prevent the reverse flow ofexhaust gases therethrough. The valve must operate in a high temperatureenvironment, have a positive checked position, and a low restrictionunchecked position to permit the free flow of injection air from thepump to the ports. The present invention provides a checkvalveincorporating features which attain the above objectives. The checkvalve has an all-metal construction for high temperature operation andincludes a metal valve disc for regulating fluid flow. The valve discincludes an annular outer ring fixedly connected to the valve body and acentral circular valve element adapted to seat against the valve inletand hingedly connected to the outer ring by a pair of flexible arcuatearms defined by a pair of concentrically disposed, diametrically opposedC-shaped slots. The arms are initially flexed to provide a closing biasagainst the inlet thereby insuring a positive checked position. The armsare additionally flexed by injection air flow to provide an easy openingunchecked position for free fluid flow to the exhaust ports.

The above and other features of the present invention will be apparentto one skilled in the art upon reading the following detaileddescription, reference being made to the accompanying drawingsillustrating a preferred embodiment of the present invention in which:

FIG. 1 is a side elevational view of an internal combustion enginehaving an air injection system incorporating an all-metal check valvemade in accordance with the present invention;

FIG. 2 is an enlarged view taken along line 22 of FIG. 1 showing thecheck valve in the closed position;

FIG. 3 is a view taken along line 3-3 of FIG. 2 showing the details ofthe valve disc and;

FIG. 4 is an enlarged view taken along line 44 of FIG. 2 showing thevalve disc in the open position.

Referring to FIG. 1, there is shown an internal combustion engine havingan air induction system 12 and an exhaust system 14 including an exhaustmanifold 16 discharging exhaust gases from the engine cylinders throughan exhaust pipe 18 to atmosphere. The engine 10 includes an airinjection system 20 including an air pump 22, a check valve 26, and anair injection manifold 28. The illustrated engine 10 is of the V-typeand includes a similar air injection manifold for the opposed bank ofcylinders.

The air pump 22 is coupled to the engine crankshaft pulley for operationin accordance with engine speed. The air pump 22 has an inlet line 32fluidly connected at the air cleaner 33 of the air induction system 12and an outlet line 34 fluidly connected to the check valve 26. The checkvalve 26 is fluidly connected to the air injection manifold 28 which hasindividual outlets 36 at the exhaust ports of the exhaust manifold 16.The check valve 26 prevents the reverse flow of exhaust gases from theexhaust manifold 16 to the air induction system 12 while permitting asubstantially unrestricted flow of injection air from the air pump 22 tothe exhaust manifold 16. This supplemental air promotes additionalburning of residual combustibles discharged to the exhaust manifold 16during engine operation.

Referring to FIG. 2, the check valve 26 has an allmetal construction andcomprises a base 40, a cover 42, and a valve disc 44. The cover 42includes a cylindrical tube 46 defining an axial inlet passage 47, anintermediate frustoconical section 48, and an annular radial flange 50.An annular rib S2 at the transition between the section 48 and theflange 50 projects axially downward from the plane of the flange 50 anddefines a circular valve seat. The end of the outlet line 34 is pressedover the outer surface of the tube 46 and is fixed thereto by a clamp54.

The base 40 includes a cylindrical tube 56 defining an outlet passage57, a stepped hub section 58, and an annular radial flange 60. Theflange 60 is crimped over the flange to fixedly assemble the base 40 andthe cover 42 with the valve disc 44 being sandwiched therebetween. Theinterior surfaces of the sections 48 and 58 between the inlet passage 47and the outlet passage 57 generally define a valving chamber 61. Aplurality of inwardly projecting ledges 62 are formed in the hub section58 and establish stop surfaces for the valve disc 44 as hereinafterdescribed.

Referring to FIG. 3, the metal valve disc 44 includes a pair of coaxialcircumferentially overlapping C- shaped slots 63 and 64 having theirends defining therebetween a pair of diametrically opposed web sections66, 68. The web sections 66, 68 are interconnected by a pair of flexiblearcuate arms 70, 72. The arms 70, 72 are diametrically opposed and eachrespectively extends between the relatively rigid web sections 66, 68.The inner slot 64 inwardly defines a circular, disc check valve member74. The outer slot 63 outwardly defines an annular outer ring 76, theperiphery of which is clamped between the flanges 50 and 60.

As shown in FIG. 2, the check valve member 74 seats against the rib 52in the closed or checked position. Inasmuch as the rib 52 projectsaxially beyond the flange 50, the arms 70, 72 are initially flexed toprovide a closing bias when the air pump 22 is not operating. Thisclosing bias will securely seat the valve member 74 to prevent thereverse flow of exhaust gases from the manifold 16 to the air inductionsystem 12.

The injection air flow from the air pump 22 will urge the check valvemember 74 to the open or unchecked position shown in FIG. 4 byadditional flexing of the arms 70, 72. This will provide a substantiallyunrestricted cylindrical flow path past the valve member 74 forpermitting the free flow of air from the pump 22. The ledges 62 engagethe lower surface of the check valve member 74 to limit the openingmovement.

The all-metal construction of the check valve 26 will withstand the highoperating temperature associated with its proximity to the exhaustmanifold 16. The selfseating of the valve element 74 will provide apositive checked condition to prevent the reverse flow of exhaust gasesand the extremely long flexible sections defined by the arms 70, 72 willprovide for substantially unrestricted injection air flow in theunchecked direction.

Although only one form of this invention has been shown and described,other forms will be readily apparent to those skilled in the art.Therefore, it is not intended to limit the scope of this invention bythe embodiment selected for the purpose of this disclosure but only bythe claim which follows.

What is claimed is:

1. In an air injection system of an internal combustion engine having anengine driven air pump fluidly connected to the engine exhaust manifold,an all-metal check valve for permitting the forward flow of air from thepump and blocking the reverse flow of exhaust gases from the exhaustmanifold to the air pump comprising: a two-piece valve body defining achamber, one piece of the valve body having an inlet for fluidconnection to the exhaust manifold; the other piece of valve body havingan outlet for fluid connection to the exhaust manifold; a circular valvedisc in said chamber having an outer ring fixed between said one pieceand said other piece, a first C-shaped slot formed in said valve discradially inwardly of said outer ring defining a first web sectionbetween the ends thereof connected to said outer ring; a second C-shapedslot formed in said valve disc concentrically within said first C-shapedprojecting valve seat on said one piece of the valve body surroundingsaid inlet and engaging said flexible valve for initially flexing saidarms between said relatively rigid diametrically opposed webs to providea bias to a closed position of said valve against said seat for blockingthe reverse flow of exhaust gases, said arms being further flexed byforward fluid flow from the air pump to position said valve in an openposition with respect to said seat for permitting fluid flow from thechamber to the exhaust manifold.

1. In an air injection system of an internal combustion engine having an engine driven air pump fluidly connected to the engine exhaust manifold, an all-metal check valve for permitting the forward flow of air from the pump and blocking the reverse flow of exhaust gases from the exhaust manifold to the air pump comprising: a two-piece valve body defining a chamber, one piece of the valve body having an inlet for fluid connection to the exhaust manifold; the other piece of valve body having an outlet for fluid connection to the exhaust manifold; a circular valve disc in said chamber having an outer ring fixed between said one piece and said other piece, a first C-shaped slot formed in said valve disc radially inwardly of said outer ring defining a first web section between the ends thereof connected to said outer ring; a second C-shaped slot formed in said valve disc concentrically within said first C-shaped slot in circumferential overlapping relationship with said first web section; said second C-shaped slot defining a flexible valve concentrically within said outer ring and further defining a second web section between the ends thereof diametrically opposed to said first web section and joined to said valve disc, said slots defining therebetween a pair of diametrically opposed arcuate arms extending between said web sections each of said arms having greater flex than said web sections; and a projecting valve seat on said one piece of the valve body surrounding said inlet and engaging said flexible valve for initially flexing said arms between said relatively rigid diametrically opposed webs to provide a bias to a closed position of said valve against said seat for blocking the reverse flow of exhaust gases, said arms being further flexed by forward fluid flow from the air pump to position said valve in an open position with respect to said seat for permitting fluid flow from the chamber to the exhaust manifold. 